Embodiments of the disclosed technology provide an array substrate and a liquid crystal display.
Liquid crystal displays are the commonly used flat panel displays at present, and thin film transistor liquid crystal displays (TFT-LCDs) are the main kind of liquid crystal displays. A TFT-LCD typically comprises an array substrate with an array structure.
FIG. 1A shows a partial top view of a typical array substrate, and FIG. 1B shows a cross sectional view taken along line A-A in FIG. 1A.
As shown in FIG. 1A and FIG. 1B, the array substrate manufactured with a conventional four-mask process generally comprises a base substrate 1 and data lines 5 and gate lines 2 that are crossed each other on the base substrate 1. The data lines 5 and the gate lines 2 collectively define a plurality of pixel units arranged in a matrix form, and each pixel unit comprises a thin film transistor (TFT) switch and a pixel electrode 11, and the TFT switch comprises a gate electrode 3, a source electrode 7, a drain electrode 8 and an active layer 6. For the pixel unit, the gate electrode 3 of the TFT is connected with one gate line 2, the source electrode 7 is connected with one data line 5, the drain electrode 8 is connected with the pixel electrode 11 of the pixel unit through a passivation hole 10, and the active layer 6 is formed between the source and the drain electrodes 7 and 8 and the gate electrode 3. A gate insulation layer 4 is formed between the gate electrode 3 and the active layer 6, a passivation layer 9 is formed between the pixel electrode 11 and the drain electrode 8, and the pixel electrode 11 is connected with the drain electrode 8 through the passivation layer via hole 10. The gate lines 2, the data lines 5, the gate electrodes 3, the source electrodes 7, the drain electrodes 8, the pixel electrodes 11 and the like can be collectively referred to as conductive patterns, while the gate insulation layer 4, the passivation layer 9 and the like can be collectively referred to as insulation layers.
A TFT-LCD needs an external light source, such as a backlight, for display; however, if the active layers of the TFTs on array substrate are illuminated by the backlight, the TFTs trend to give rise to leakage currents (Ioff), which degrades display quality of the TFT-LCD, thus it is necessary to form a black matrix on the opposite substrate (e.g., a color filter substrate) to the array substrate, decreasing the aperture ratio of the TFT-LCD.